Composite wall structures are known wherein concrete is poured in elongated channels formed by opposed wall structures and examples thereof are described in U.S. Pat. Nos. 3,195,699 and 3,481,093. In the first one of these patents, the forms are constituted by wet-resistant cardboard or strong paper spaced by Z cross-section flanges which are glued to the wall skins. Cavities are provided in these webs for concrete to flow between the webs to form a simple concrete wall. In the second one of these patents, the wall structure is provided by two spaced-apart metal sheets which are self-supporting and wherein a space defined between the sheets is filled with a bonding material whereby these panels are interconnected to form a solid core wall structure and form in a simple concrete wall. U.S. Pat. No. 4,433,522 also describes a wall structure comprising a plurality of steel elements interconnected together to form a hollow wall with joints therein and wherein concrete can be poured within the hollow wall to constitute a protective wall structure having a high resistance to blasts and fragments. It is also known to interconnect wall elements in two parallel rows with the wall elements being laid in courses and interconnected by connecting rods to maintain the wall elements in place when concrete is poured therebetween. Such a wall structure is described in U.S. Pat. No. 4,321,779 and form a simple concrete wall.